Environmental Impact Assessment

The EIA Regulations include certain requirements to the manner in which to conduct an environmental impact assessment. Aditionally, there are a number of documents that describe good practice guidance in environmental impact assessment.
The approach to the EIA has been informed by:

• Statutory requirements, as set out in the EIA Directive and the EIA Regulations 1999.
• Consultation with statutory and non-statutory consultees.
• Current guidance and best practice.
• The specific nature and location of the proposed scheme.
• The qualifications of the EIA team and their professional experience on comparable projects.

Government guidance

An EIA should be undertaken having regard to the following Government guidance documents:

• Department of the Environment, Transport and the Regions (DETR) (1999) Circular 2/99: Environmental Impact Assessment.
• DETR and the National Assembly for Wales (2000) Environmental Impact Assessment: A Guide To Procedures.
• Preparation of Environmental Statements for Planning Projects that require Environmental Impact Assessment: A Good Practice Guide, DOE, 1995
• Office of the Deputy Prime Minister (ODPM), Note on Environmental Impact Assessment Directive for Local Planning Authorities 1999 EIA Regulations, July 2002.

Between June and September 2006 the UK Government consulted on draft updated versions of the above documents. These are being updated to reflect, inter alia, the lessons derived from the large amount of EIA case law that has arisen in the preceding six or seven years, and also the ongoing development of EIA as a professional discipline. Although it is acknowledged that they are in draft form, the following documents have nevertheless been reviewed and lessons drawn where appropriate:

• Department for Communities and Local Government (2006) Amended Circular on Environmental Impact Assessment. A Consultation Paper.
• Department for Communities and Local Government (2006) Environmental Impact Assessment: A guide to good practice and procedures. A Consultation Paper.

Design and environmental interface

Environmental issues have influenced the development of the scheme in that they have been incorporated from the outset of the design process and have been considered as part of decision-making. This was achieved through a co-ordinated relationship between project design, EIA and project management. EIA is intended to be an iterative process rather than an assessment of end state. Applied in this way there is a much greater opportunity for environmental effects to be reduced or eliminated through changes to design rather than by means of offsetting or compensating. Where the EIA process has influenced the design decisions this is reported within the relevant environmental assessment chapter.

Baseline condition and assessment of effects

The EIA has considered the likely environmental effects of the proposed development based upon current knowledge of the site and the surrounding environment. Following the findings of various studies contributing to the EIA, ways of avoiding, reducing or offsetting any potential significant adverse effects (collectively known as 'mitigation measures') have been identified.
An EIA should consider both positive and negative impacts during both the construction phase of the development and once it is completed. In accordance with the legislative requirements, direct, indirect, secondary and cumulative; short, medium and long term; permanent and temporary; and positive and negative effects have been addressed where applicable.

Significance of effects

A "significant" effect may be broadly defined as one that should be brought to the attention of those involved in the decision-making process, and could result in a condition on the planning permission or even refusal of planning permission. This definition is prescribed to varying degrees by statute, EU and national guidelines and standards, and precedents established in previous EIAs.

Guidance on significance is mainly of a generic nature and practitioners have been obliged to develop definitions for specific topics and projects based on the locality. It is broadly accepted, however, that significance reflects the relationship between a number of factors:

• the magnitude or severity of an impact (i.e. the actual change taking place to the environment)
• the importance or value of the affected resource or receptor
• the duration involved
• the reversibility of the effect
• the number and sensitivity of receptors

The severity of an impact is often quantifiable in terms of, for example, extent of land-take or predicted change in air quality. The sensitivity, importance or value of a resource or receptor is normally derived from:

• Its designated status within the land use planning system.
• The number of individual receptors, such as residents.
• An empirical assessment on the basis of characteristics such as rarity or condition.
• Its ability to absorb change.

Significant effects are likely to occur where valuable or sensitive resources, or numerous receptors, are subject to impacts of considerable severity. Effects are unlikely to be significant where low value or non-sensitive resources, or a small number of receptors, are subject to minor impacts. In practical terms significance is often an issue of degree. Within the methodology that is used in the EIA for the Radbourne Lane development this is recognised by adopting the five levels of significance as described in the draft EIA guide to good practice and procedures.

These five levels of significance are:

• Severe: These effects represent key factors in the decision-making process. They are generally, but not exclusively associated with sites and features of national importance and resources/features which are unique and which, if lost, cannot be replaced or relocated.
• Major: These effects are likely to be important considerations at a regional or district scale but, if adverse, are potential concerns to the project, depending upon the relative importance attached to the issue during the decision making process.
• Moderate: These effects, if adverse, while important at a local scale, are not likely to be key decision making issues. Nevertheless, the cumulative effect of such issues may lead to an increase in the overall effects on a particular area or on a particular resource.
• Minor: These effects may be raised as local issues but are unlikely to be of importance in the decision making process. Nevertheless, they are of relevance in the detailed design of the project.
• Neutral: no effect, not significant. Irrespective of other effects.

Allocation of the significance of effects in intermediate situations will be a matter for professional judgement in each topic area. Within this ES, the following generic matrix (Table 1.2) is used to define the level of significance of effects. In some cases analogous matrices for the various specialist topics are used, and where these use different assessment criteria this is clearly stated within the relevant chapter.